Traditional circuit-switched networks have been designed and optimized for the time-sensitive delivery of voice traffic. As a result, the Public Switched Telephone Network (PSTN) has provided highly predictable quality of service for voice and has become the standard infrastructure for voice transmission. The PSTN delivers toll quality speech primarily by allocating dedicated bandwidth while using non-compression analog-to-digital encoding techniques. Likewise, transmission of predictable voice speech quality has been an important concern for voice that travels through a packet based infrastructure, such as the Internet, because such networks may alter the time sensitive qualities of speech. Recently, the deployment of data networks that facilitate the transmission of voice over Internet Protocol (VoIP), voice over asynchronous transfer mode (ATM), voice over frame relay, wireless, and traditional wireline has created a need to assess the quality of speech being transmitted. When VoIP technology is deployed for voice services on an enterprise or commercial network, users expect a service quality that is tantamount to that of the Public Switched Telephone Network (PSTN).
One of the key drivers behind VoIP network deployments is lower capital costs of implementing voice transmission compared with traditional circuit-switched network deployments. However, it is important that the appropriate IP network architectures and configurations, and VoIP systems, be implemented to deliver appropriate levels of voice service quality. This means that up-front design and purchasing decisions will be critical in the success and payoff of a VoIP strategy. Such decisions begin with assessing the IP network for VoIP performance, prior to VoIP deployment. If the performance of an element in the VoIP communication system degrades the quality of voice significantly, the resulting speech transmitted will be unintelligible. Assessing the voice quality of a VoIP network has not been a simple task.
Voice, being a real-time media, requires quality of service tools that address factors that may affect voice clarity in a VoIP network. Unfortunately, a pre-deployment network assessment may be extremely difficult to obtain. Further, a disadvantage of deploying a VoIP network is the inability to easily and objectively measure the degradation of voice service quality contributed by one or more network elements within a voice transmission network (such as a VoIP network).
There are many factors that influence quality of service of a voice transmission. Of these factors, voice quality may be the most meaningful from the end user's perspective since end users decide what communication services they will pay for and from whom they will buy them. It is from the perspective of the end user that voice quality scores are best defined.
Traditional methods measure voice quality by way of subjective and/or objective voice quality analysis between two endpoints of a voice communication system. One or more algorithms may be applied to the voice received to generate a voice quality score. However, obtaining these voice quality scores at various points along a network is a difficult if not impossible task. Furthermore, the inability to effectively provide this information to a user, such as a network engineer, provides an inefficient and costly approach to designing and troubleshooting a voice communication system.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.